What is the difference between single entry visa and multiple entries visa?

What is the difference between single entry visa and multiple entries visa?

There is a big difference between a single entry visa and a multiple entries visa which lies on the number of times you can enter and exit Vietnam.

The single entry visa allows you to enter and exit Vietnam ONCE only. Your single entry will automatically become invalid once you exit Vietnam no matter your actual exit date is earlier than the granted exit date. In case you want to come back Vietnam, you are required to obtain a new visa.

The multiple entries visa allows you to enter and exit Vietnam as many times as you wish. It means that you can exit and then re-enter Vietnam at any time during your visa validity. Your multiple entries visa will become invalid on the granted exit date.